"Throughout a lifetime of enormous change, Her Majesty Queen Elizabeth II has maintained a remarkable sense of grace, stability and continuity, above all through her sustained and dedicated service to her role and her peoples.
"In doing so, she has earned the affection and respect of people all over the world."
Sir Jerry and Lady Janine planned to hold a celebratory dinner at Government House this evening.
Prime Minister John Key, who is in China, said he had written to the Queen on behalf of the New Zealand government.
"Like many New Zealanders, I greatly admire Queen Elizabeth's lifetime of dedicated service and leadership," he said.
"Queen Elizabeth is a beloved figure here and we value her role as Queen of New Zealand. I am sure New Zealanders will join with me in wishing her a very Happy Birthday."
New Zealand Post is marking the occasion with a special series of stamps and a limited edition silver coin.
Three "lenticular" stamps which feature nine different images have been produced.
"We wanted to produce something different for this very special 90th birthday," said New Zealand Post's head of stamps and coins Simon Allison.
"Queen Elizabeth II is the first British Monarch to reach this impressive milestone, and the stamps and coins are a beautiful keepsake for the occasion."
The 1oz silver coin features the Queen at her christening.